The invention relates to an audio editing system and to a video editing system incorporating an audio editing system.
Video editing systems are available for creating an edited video sequence from a plurality of video clip portions. The video clip portions may be selected from different video clips, for example when it is desired to dissolve from one scene to another in the edited sequence, or they may be selected from one video clip, for example when it is desired to remove a central portion from the one video clip. An example of a known video editing system is described in European Patent Application No. 93301889.7 published as EP-A-560624 and U.S. application Ser. No. 08/030,823 the teachings of which are incorporated herein by reference.
Video is usually accompanied by audio in the form of plural audio tracks representing, say, stereo left and right channels, background music and a narrative. Thus, each video clip will have one or more associated audio clips. Video editing systems therefore commonly include an audio editing system to enable appropriate editing of the audio clips to suit the editing of the video clips.
The Quantel Henry editing system embodies the video editing system described in the aforementioned EP-A-560,624 and includes an audio editing system which enables certain audio editing operations to be effected. Referring now to FIG. 1 of the accompanying drawings, the Quantel Henry editing system enables two video clips 1, 2 and associated audio clips 3, 4 to be selectively combined to produce a resultant video sequence 5 and associated resultant audio sequence 6. The two video clips 1, 2 and the two audio clips 3, 4 are joined at an edit point 7 either by a simple cut operation or by a more complicated wipe or dissolve operation. The video and audio clips 1 to 4 each comprise a portion 8 to 11 before or after the edit point 7 that may or may not contribute to the resultant video and audio sequences. The portions 8 to 11 are generally referred to as "tails". If the desired result is a wipe or dissolve across the edit point then the tails 8 to 11 will make a contribution to the resultant video and audio sequences. The data representing the video and audio tails should therefore be retained at least until such time as the user is satisfied with the resultant video and audio sequences.
There exists, however, a problem which can arise under two different circumstances. The first circumstance is represented by the situation depicted in FIGS. 2, 3 and 4 of the accompanying drawings. FIG. 2 shows a desired edit in which a first video/audio clip A is to be combined with a second video/audio clip B to produce a resultant video/audio sequence R. The first clip A has a short video out-tail 12 and a short audio out-tail 13 and the second clip has a short video in-tail 14 and a short audio in-tail 15. The in-tails 12, 13 and the out-tails 14, 15 are said to be short because the in-tails 12, 13 begin after the start 16 of the resultant video/audio sequences and the out-tails finish before the end 17 of the resultant video/audio sequences. FIG. 3 shows an alternative edit in which the second clip B' is combined with the first clip A' in such a manner that the clips have long in-tails 18, 19 and long out-tails 20, 21, because the in-tails 18, 19 begin before the start 16' of the resultant video/audio sequences R' and the out-tails 20, 21 finish after the end 17' of the resultant video/audio sequences. Hitherto, it has been assumed that the long audio tails are not required. One reason for assuming this is that it enables storage space to be made available for storing other audio. Another reason is that with multiple audio tracks for each video clip it soon becomes difficult to keep track of all the audio data including tails within the system.
An error that editors occasionally make during editing is to reverse the manner in which the two video/audio clips are combined so that instead of being combined as shown in FIG. 2 they are combined as shown in FIG. 3. Herein lies a problem. It is a simple matter to undo the effect of combining the video clips using the editing system described in the aforementioned EP-A-560,624, but because the long audio tails are discarded when clips A' and B' are combined it is not so straightforward to undo the effect of combining the audio clips.
As represented by FIG. 4 of the accompanying drawings, when the clips A' and B' are separated they produce two video/audio clips A" and B". However, the audio clip A" merely comprises a short portion 22 near the start and the audio clip B" merely comprises a short portion 23 at the finish because the audio at the portions 24 and 25 were discarded during the previous incorrect combining operation. Therefore, if the video/audio clips A" and B" are combined they will produce a resultant sequence R" in which the audio contains a large gap 26 between the short start portion 22 and the short finish portion 23. Hitherto, the only solution has been to replace the clip or clips from which audio data has been discarded with replacement data representing the entire unedited clip.
The second circumstance can arise in the situation represented by FIGS. 5 to 7 of the accompanying drawings. As shown in FIG. 5 of the accompanying drawings a resultant video/audio sequence R is produced from three initial video/audio clips A, B, C by editing together clips A and B at a first edit point 30 and editing together clips B and C at a second edit point 31. Thus, clip A will comprise an out-tail 32, clip B will comprise an in-tail 33 and an out-tail 34, and clip C will comprise an in-tail 35. It should be noted that there is no overlap of an in-tail from one clip with an out-tail from another clip. FIG. 6 of the drawings shows a similar situation where three video/audio clips A', B', C' are combined to produce an resultant video/audio sequence R' and thus each clip A', B', C' has an associated in-tail and/or out-tail 36 to 39. It will be noted that the out-tail 36 of clip A' and the in-tail 39 of clip C' overlap. Hitherto, it has been assumed that the portions of the two tails 36 and 39 that overlap are not required and the data for either or both of the overlapping portions has been discarded. As shown in FIG. 6 only the portion 40 of the audio in-tail 39 of clip C' has been deleted but equally the corresponding portion of the audio out-tail 36 could have been deleted as well as or instead of the portion 40.
Occasionally editors will inadvertently misposition clips so that there are overlapping tails such as shown in FIG. 6. For the purpose of the following explanation it should be assumed that the arrangement shown in FIG. 5 is the desired arrangement and that the arrangement shown in FIG. 6 has been reached unintentionally by the editor. It is a simply matter to undo the effect of combining the video clips B' and C' using the video editing system described in EP-A-560,624 but the discarding of the portion 40 means that it is not so straightforward to undo the effect of combining audio clips B' and C'. As shown in FIG. 7, simply moving the clip C" to the correct position will produce a resultant sequence R" in which there is a gap 41 in the audio sequence resulting from the deletion of the portion 40 during the previous, incorrect, combining of the clips. Hitherto, the only solution has been to replace the clip or clips from which audio data has been discarded with data representing an unedited and complete version of the clip from an off-line source.
The present invention aims to overcome the above discussed problems.
According to one aspect of the invention there is provided an audio editing system for selectively combining portions of plural audio clips to produce a resultant audio sequence, in which system a visual representation is displayable of the plural audio clips identifying audio clip portions selected to contribute to the audio sequence and all audio clip portions not selected to contribute to the audio sequence.
The displaying of a visual representation of all audio clip portions not selected to contribute to the audio sequence facilitates subsequent re-editing by enabling direct access to the audio portions not selected in the event that a change to the selected combination is required for example.
According to another aspect of the invention there is provided an audio editing system for creating an edited audio sequence from a plurality of audio clip portions, in which system the plurality of audio clip portions are represented by digital data stored in an audio store, and editing data is generated during editing identifying locations in the store at which data representing audio clip portions selected to contribute and all audio clip portions not selected to contribute to the edited audio sequence.
The generation of editing data representing all audio clip portions not selected to contribute to the edited audio sequence facilitates editing by enabling the data to be accessed directly from the audio store for example if a change to the edited audio sequence is required.
The audio editing system may be incorporated into a video editing system for selectively combining portions of plural video clips and associated plural audio clips to produce a resultant video sequence and associated audio sequence.
According to a further aspect of the invention there is provided a video editing system for combining plural initial video clips each having one or more audio clips associated therewith to produce a resultant video sequence having one or more associated resultant audio sequences, the system comprising: an audio store for storing data representing each of the audio clips; user operable input means for generating control signals in response to user manipulation thereof; an editing processor responsive to said control signals for generating edit data defining user desired editing operations to be applied to the audio clips; an edit data store for storing the edit data; and a display processor for generating from the edit data, data defining an image representing the audio clips, and wherein the editing processor is arranged to generate data identifying portions of the audio clips selected to contribute to the resultant audio sequence and identifying all other portions of the audio clips not selected to contribute to the resultant audio sequence, the generated data being stored in the edit data store; and the data generated by the display processor defines an image representing both the portions of the audio clips selected to contribute to the resultant audio sequence and all other portions of the audio clips not selected to contribute to the resultant audio sequence.
The above and further features of the invention together with advantages thereof will become clearer from consideration of the following detailed description of an exemplary embodiment of the invention given with reference to the accompanying drawings.